Sympathomimetic Effects of Acute E‐Cigarette Use: Role of Nicotine and Non‐Nicotine Constituents

• Published in: Journal of the American Heart Association Vol. 6; no. 9
• Main Authors: Moheimani, Roya S., Bhetraratana, May, Peters, Kacey M., Yang, Benjamin K., Yin, Fen, Gornbein, Jeffrey, Araujo, Jesus A., Middlekauff, Holly R.
• Format: Journal Article
• Language: English
• Published: England John Wiley and Sons Inc 01-09-2017; Wiley
• Subjects: Adult; Cardiovascular Diseases - etiology; Cardiovascular Diseases - physiopathology; Cross-Over Studies; electronic cigarettes; Electronic Nicotine Delivery Systems; Female; Ganglionic Stimulants - adverse effects; Healthy Volunteers; Heart Rate - drug effects; heart rate variability; Humans; Male; Middle Aged; nicotine; Nicotine - adverse effects; Original Research; oxidant stress; Smoking - adverse effects; sympathetic nervous system; Sympathetic Nervous System - drug effects; Sympathetic Nervous System - physiopathology; Sympathomimetics - adverse effects; tobacco; Young Adult; oxidant stress; nicotine; tobacco; heart rate variability; sympathetic nervous system; electronic cigarettes
• ISSN: 2047-9980; 2047-9980
• DOI: 10.1161/JAHA.117.006579

Background
Chronic electronic (e) cigarette users have increased resting cardiac sympathetic nerve activity and increased susceptibility to oxidative stress. The purpose of the present study is to determine the role of nicotine versus non‐nicotine constituents in e‐cigarette emissions in causing these pathologies in otherwise healthy humans.
Methods and Results
Thirty‐three healthy volunteers who were not current e‐cigarette or tobacco cigarette smokers were studied. On different days, each participant used an e‐cigarette with nicotine, an e‐cigarette without nicotine, or a sham control. Cardiac sympathetic nerve activity was determined by heart rate variability, and susceptibility to oxidative stress was determined by plasma paraoxonase activity. Following exposure to the e‐cigarette with nicotine, but not to the e‐cigarette without nicotine or the sham control, there was a significant and marked shift in cardiac sympathovagal balance towards sympathetic predominance. The decrease in high‐frequency component and the increases in the low‐frequency component and the low‐frequency to high‐frequency ratio were significantly greater following exposure to the e‐cigarette with nicotine compared with exposure to the e‐cigarette without nicotine or to sham control. Oxidative stress, as estimated by plasma paraoxonase, did not increase following any of the 3 exposures.
Conclusions
The acute sympathomimetic effect of e‐cigarettes is attributable to the inhaled nicotine, not to non‐nicotine constituents in e‐cigarette aerosol, recapitulating the same heart rate variability pattern associated with increased cardiac risk in multiple populations with and without known cardiac disease. Evidence of oxidative stress, as estimated by plasma paraoxonase activity, was not uncovered following acute e‐cigarette exposure.